package 常用类.日期时间;

/**
 * @Projectname java_based
 * @Filename JDK8DateTimeTest
 * @Author an
 * @Data 2022/7/16 14:41
 * @Description TODO
 */
import org.junit.Test;

import java.time.*;
import java.time.format.DateTimeFormatter;
import java.time.format.FormatStyle;
import java.time.temporal.TemporalAccessor;
import java.util.Date;

/**
 * jdk 8中日期时间API的测试
 *
 */
public class JDK8DateTimeTest {

    @Test
    public void testDate(){
        //偏移量
        Date date1 = new Date(2020,9,8);
        System.out.println(date1);  //Fri Oct 08 00:00:00 CST 3920

        Date date2 = new Date(2020 - 1900,9 - 1,8);
        System.out.println(date2); //Tue Sep 08 00:00:00 CST 2020
    }


    /**
     * LocalDate、LocalTime、LocalDateTime的使用
     *
     */
    @Test
    public void test1(){
        //now():获取当前的日期、时间、日期+时间
        LocalDate localDate = LocalDate.now();
        LocalTime localTime = LocalTime.now();
        LocalDateTime localDateTime = LocalDateTime.now();

        System.out.println(localDate);
        System.out.println(localTime);
        System.out.println(localDateTime);

        //of():设置指定的年、月、日、时、分、秒。没有偏移量
        LocalDateTime localDateTime1 = LocalDateTime.of(2020, 10, 6, 13, 23, 43);
        System.out.println(localDateTime1);

        //getXxx()：获取相关的属性
        System.out.println(localDateTime.getDayOfMonth());
        System.out.println(localDateTime.getDayOfWeek());
        System.out.println(localDateTime.getMonth());
        System.out.println(localDateTime.getMonthValue());
        System.out.println(localDateTime.getMinute());

        //体现不可变性
        //withXxx():设置相关的属性
        LocalDate localDate1 = localDate.withDayOfMonth(22);
        System.out.println(localDate);
        System.out.println(localDate1);

        LocalDateTime localDateTime2 = localDateTime.withHour(4);
        System.out.println(localDateTime);
        System.out.println(localDateTime2);

        //不可变性
        LocalDateTime localDateTime3 = localDateTime.plusMonths(3);
        System.out.println(localDateTime);
        System.out.println(localDateTime3);//plusMonths表示 +3 个月

        LocalDateTime localDateTime4 = localDateTime.minusDays(6);
        System.out.println(localDateTime);
        System.out.println(localDateTime4);
    }


    /**
     * Instant的使用
     */
    @Test
    public void test2(){
        //now():获取本初子午线对应的标准时间
        Instant instant = Instant.now();
        System.out.println(instant);    //2022-07-16T07:29:57.562Z

        //添加时间的偏移量
        OffsetDateTime offsetDateTime = instant.atOffset(ZoneOffset.ofHours(8));//东八区
        System.out.println(offsetDateTime); //2022-07-16T15:33:29.600+08:00

        //toEpochMilli():获取自1970年1月1日0时0分0秒（UTC）开始的毫秒数  ---> Date类的getTime()
        long milli = instant.toEpochMilli();
        System.out.println(milli);  //1657956809600

        //ofEpochMilli():通过给定的毫秒数，获取Instant实例  -->Date(long millis)
        Instant instant1 = Instant.ofEpochMilli(1657956809600L);
        System.out.println(instant1);   //2022-07-16T07:33:29.600Z
    }

    /**
     * DateTimeFormatter:格式化或解析日期、时间
     *     类似于SimpleDateFormat
     */
    @Test
    public void test3(){
        //方式一：预定义的标准格式。如：ISO_LOCAL_DATE_TIME;ISO_LOCAL_DATE;ISO_LOCAL_TIME
        DateTimeFormatter formatter = DateTimeFormatter.ISO_LOCAL_DATE_TIME;
        //格式化:日期-->字符串
        LocalDateTime localDateTime = LocalDateTime.now();
        String str1 = formatter.format(localDateTime);
        System.out.println(localDateTime);
        System.out.println(str1);//2022-07-16T20:53:54.619

        //解析：字符串 -->日期
        TemporalAccessor parse = formatter.parse("2022-07-16T20:53:54.619");
        System.out.println(parse);

        //方式二：
        //本地化相关的格式。如：ofLocalizedDateTime()
        //FormatStyle.LONG / FormatStyle.MEDIUM / FormatStyle.SHORT :适用于LocalDateTime
        DateTimeFormatter formatter1 = DateTimeFormatter.ofLocalizedDateTime(FormatStyle.LONG);
        //格式化
        String str2 = formatter1.format(localDateTime);
        System.out.println(str2);//2022年7月16日 下午08时54分34秒

        //本地化相关的格式。如：ofLocalizedDate()
        //FormatStyle.FULL / FormatStyle.LONG / FormatStyle.MEDIUM / FormatStyle.SHORT : 适用于LocalDate
        DateTimeFormatter formatter2 = DateTimeFormatter.ofLocalizedDate(FormatStyle.MEDIUM);
        //格式化
        String str3 = formatter2.format(LocalDate.now());
        System.out.println(str3);//2022-7-16


        //重点： 方式三：自定义的格式。如：ofPattern(“yyyy-MM-dd hh:mm:ss”)
        DateTimeFormatter formatter3 = DateTimeFormatter.ofPattern("yyyy-MM-dd hh:mm:ss");
        //格式化
        String str4 = formatter3.format(LocalDateTime.now());
        System.out.println(str4);//2022-07-16 08:54:34

        //解析
        TemporalAccessor accessor = formatter3.parse("2022-07-16 08:54:34");
        System.out.println(accessor);

    }

}
